A comparative study of small field total scatter factors and dose profiles using plastic scintillation detectors and other stereotactic dosimeters: the case of the CyberKnife.

Purpose: Small-field dosimetry is challenging, and the main limitations of most dosimeters are insufficient spatial resolution, water nonequivalence, and energy dependence. The purpose of this study was to compare plastic scintillation detectors (PSDs) to several commercial stereotactic dosimeters by measuring total scatter factors and dose profiles on a CyberKnife system.

Methods: Two PSDs were developed, having sensitive volumes of 0.

High physician adherence to phenotype-specific asthma guidelines, but large variability in phenotype assessment in children.

Background: The implementation of international pediatric asthma guidelines hinges on the distinction between intermittent and persistent phenotypes and the prescription of recommended phenotype-specific pharmacotherapy.

Objectives: To ascertain key factors associated with specialist-confirmed phenotype and document physicians' adherence to practice recommendations in an academic pediatric asthma center.

Design/methods: Using electronic health records, we identified a cohort of children aged 1-17 years who presented to a tertiary-care asthma center between 2002 and 2007 and received a diagnosis of asthma from a pediatric specialist.